This invention relates to a fly killing composition for use on the ground or other horizontal surfaces and which is especially useful in areas of high fly population such as dairy barns and poultry-keeping pens. More particularly, it is concerned with a composition that has improved fly attractant characteristics in conjunction with an unusually long useful life and is substantially impervious to the inactivating effects of moisture.
In the past, granular fly killing compositions for use in the areas described have comprised coarsely ground, granular sugar as an attractant base in conjunction with an insecticide coating thereover. Typical insecticides used in these formulations included 2,2-dichlorovinyl 0,0-dimethyl phosphate and 0,0-dimethyl 0-2,4,5-trichlorophenylphosphorothioate, each being used alone or in combination. The former is commonly referred to in the art as "DDVP", and the latter is referred to as "ronnel".
In practice however, the presently available fly killing compositions are deficient in several important respects. First, they generally exhibit only very short active fly-killing lives, which of course necessitates continual removal of spent bait and replacement thereof. For example, conventional granulated sugar based fly baits treated with DDVP alone are normally effective only for a period of about 48 hours, and even this time is lessened during extremely hot and humid weather. Similarly, a combination of DDVP and ronnel on granulated sugar usually has a maximum effective life of no longer than about 2 or 3 days. Lack of longevity is believed to be at least partly attributable to the fact that the toxicants are not significantly absorbed into the sugar attractant but reside on the surfaces of the crystals thereof and thus dissipate rather rapidly into the atmosphere, particularly during hot weather use when the pesticide is most sorely needed.
The effectiveness of these baits is further diminished because of the fact that moisture in the form of rainfall or the like serves to at least partially inactivate the composition because the sugar dissolves in rainwater and the granules either wash away or slowly disentegrate, causing rapid loss of the toxic agent. Hence, it is often necessary to replace these compositions after a rainfall because of the fact that they are no longer capable of killing flies.
Finally, some fly baits, particularly of the granulated sugar type which have only a surface coating of toxicant thereon have in fact repelled flies initially attracted thereto before the same could be killed. This is believed to occur at least in part because the shiny surfaces of the sugar granules repels the flies and the toxicant is relatively ineffective unless the insects directly contacted the active agent or are subjected to a lethal dose of the vapor thereof.
Hence, there is a great need in the art for an effective fly killing composition which attracts flies thereto without a subsequent repellent effect, is operative for an extended period of time, and can be employed without fear of rapid inactivation by virtue of adverse atmospheric conditions.